Title

Identifier

Author

Degree

Master of Science (MS)

Department

Agricultural Economics

Document Type

Thesis

Abstract

Field studies were conducted in Crowley, Louisiana and Stoneville, Mississippi in drill seeded rice to evaluate weed control, yield, and economical returns with imazethapyr programs. Red rice (Oryza sativa) and barnyardgrass (Echinochloa crus-galli) was evaluated with imazethapyr applied alone at various rates and application timings. Imazethapyr, averaged across rate, controlled red rice 89% and barnyardgrass 90% when the initial application of imazethapyr was applied at emergence followed by (fb) a second application of imazethapyr two weeks after the initial application. While imazethapyr, averaged across timing, showed no differences for red rice and barnyardgrass control. Yield and economical returns were maximized when the initial application of imazethapyr was applied at rice emergence fb a second application of imazethapyr two weeks later. Research was conducted in Crowley, Louisiana in 2008 and 2009 to evaluate the addition of different propanil formulations in mixture with a standard imazethapyr program of 70 g/ha early postemergence fb 70 g/ha late postemergence. Weeds evaluated included red rice, barnyardgrass, Texasweed (Caperonia palustris), and alligatorweed (Althernanthera philoxeroides). Weed control of all weeds evaluated with treatments consisting of a propanil formulation in mixture with imazethapyr was equivalent to, or higher, than the standard imazethapyr program. Yield and economical returns were maximized when the propanil formulation of RiceShot® or Stam M4® was in mixture with imazethapyr in the initial application. The addition of propanil in mixture with imazethapyr increased rough rice yield and economical returns due to the increased weed control Research was conducted in Crowley, Louisiana in 2008 and 2009 to evaluate the addition of a herbicide with soil residual activity in mixture with imazethapyr applied very-early postemergence fb an application of imazethapyr or imazamox two weeks after the initial application. Weeds evaluated included red rice, barnyardgrass, Texasweed, and alligatorweed. Weed control with treatments including a herbicide with soil residual activity was equivalent to or higher than imazethapyr applied alone fb imazethapyr or imazamox. Yield and economical returns were maximized with quinclorac or penoxsulam mixed with imazethapyr fb imazethapyr or imazamox. The addition of quinclorac or penoxsulam proved to be beneficial in a total weed management program.